Outside linebacker Alex Okafor, the Cardinals fourth-round pick in April, will miss the rest of the regular season with a torn biceps, coach Bruce Arians said on his weekly radio show on Tuesday, via FoxSports.com. Okafor's injury is a blow for a team that's already thin at outside linebacker.

Before the Cardinals learned the extent of the injury, Okafor had been set to make his first career start against Tampa Bay on Sunday, according to the team's official website. Arizona now only has two outside linebackers that have been on the active-roster for over a week in 35-year-old John Abraham and converted defensive end Matt Shaughnessy.

To add some depth to the position, the Cardinals signed Vic So'oto on Tuesday and promoted Dontay Moch from the practice squad. So'oto's played in 12 career games with three different teams. Moch played in one game in 2012 with the Bengals.